Synthesis Of Yttrium Aluminum Garnet Research Articles

Influence of different diffusion rates of reaction reagents on the synthesis of yttrium aluminium garnet (YAG)

Influence of different diffusion rates of reaction reagents on the synthesis of yttrium aluminium garnet (YAG)

Synthesis of yttrium aluminum garnet (Y3Al5O12, YAG) powder with nano and submicro size and high infrared transmittance using flame aerosol synthesis method

In this study, the flame aerosol synthesis (FAS) method was used to synthesize a yttrium aluminum garnet (Y3Al5O12, YAG) nanopowder. The dominant reaction route in the FAS method is the liquid route; this shaped the primary morphology of the YAG nanopowder into hollow and solid spheres. The effects of precursor concentration and annealing parameters were systematically investigated. At a precursor concentration of 0.4 mol L−1 and an annealing temperature of 1400 °C, the YAG nanopowder exhibited excellent infrared transmittance. Compared to other conventional synthesis methods, the FAS method has the advantages of high yield, low cost, and ease of obtaining a nanosized powder. The FAS method is thought to be one of the best choices for the large-scale production of YAG powders.

Rapid synthesis of YAG phosphor by facile mechanical method

AbstractIn this study, synthesis of yttrium aluminum garnet (YAG):Ce3+ phosphor powders for white light emitting diodes was investigated by mechanical method using the attrition‐type mill with no external heating and no flux in dry phase. High mechanical energy input to the starting powder mixture of Y2O3, Al2O3 and CeO2 achieved the synthesis of YAG:Ce3+ without any flux materials. X‐ray diffraction patterns of the processed powders after 5 min processing revealed the peaks of YAG were clearly identified. The maximum temperature of the mill chamber during the processing was 240℃. The YAG phosphor obtained by the mechanical method revealed the internal quantum yield of 65% in the case of the sample mechanically processed under a reducing atmosphere. The synthesized powder showed granule structure consisting of submicron size of YAG particles, which is better handling for the fabrication of light emitting diode devices.

Effect of Complex Ceramic Oxide Nanoparticles Addition on the Corrosion Behavior of Stainless Steel in Artificial Sea Water: Physical Chemistry Approach

A novel method of electrochemical synthesis of yttrium aluminum garnet (YAG: Al5Y3O12) is successfully developed in the mixture of YCl3 and AlCl3 aqueous solution. The electrosynthesized YAG are further annealed and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Ppy/YAG thin film is formed electrochemically on the surface of the stainless steel (SS). The anti-corrosive behavior of polypyrrole films in the presence of YAG nanoparticles synthesized by electropolymerisation on stainless steel (SS) electrodes have been investigated in artificial sea water solutions using potentiodynamic polarization and electrochemical impedance spectroscopy. The undoped polypyrrole synthesized in the presence of YAG nanoparticles coated electrodes offered a noticeable enhancement of protection against corrosion processes. Facile synthesis of YAG and Ppy/YAG nanocomposite and more efficient protection effect of nanocomposite film are main important novelty of the presented work.

Sol-gel synthesis of yttrium aluminum garnet (YAG): effects of the precursor nature and concentration on the crystallization

The sol–gel synthesis of yttrium aluminum garnet (YAG) was performed using different metal precursors (salts and alkoxides of aluminum and yttrium) and metal concentrations (up to a concentration factor of 7.4). The cross-reactivity of the aluminum and yttrium precursors is not clear, and generally, the sol–gel process leads to polyphasic samples consisting of hexagonal YAlO3 and a monoclinic yttrium-aluminum oxide. Nevertheless, the high reactivity of the yttrium precursor can be offset by the use of an aluminum alkoxide and yttrium salt as the precursors, which results in the synthesis of pure-phase YAG at 1000 °C. The effects of the metal concentration in the sol–gel synthesis on the crystallite size of the resulting YAG are reported for the first time and are found to be significant with the crystallite size varying from 55 to 123 nm. Repeated experiments demonstrate that the proposed synthesis protocol is relatively robust.

Solid-state synthesis of YAG powders through microwave coupling of oxide/carbon particulate mixtures

The rapid synthesis of yttrium aluminum garnet (Y3Al15O12, YAG) powder was investigated through the use of microwave irradiation of the oxide precursor system. For this investigation, an external hybrid heating source was not used. Instead, the rapid heating of the precursor materials (yttria and alumina powders, which are typically transparent to 2.45 GHz microwaves) was initiated by mixing an intrinsic absorbing material (carbon) into the original oxide precursors. The effect of the carbon characteristics, such as carbon source, concentration, particle size, and agglomerate microstructure were evaluated on the efficiency of coupling and resultant oxide reaction. The microwave power was varied to optimize the YAG conversion and eliminate intermediate phase formation. Interactions between the conductive carbon particles and the dielectric oxides within the microwave exposure produced local arching and micro-plasma formation within the powder bed, resulting in the rapid formation of the refractory YAG composition. This optimal conduction led to temperatures of 1000 °C that could be achieved in less than 5 min resulting in the formation of > 90 vol% YAG. The understanding of a conductor/dielectric particulate system in this work, provided insight into possible application of similar systems where microwave irradiation could be used for enhanced solid-state formation, local melting events, and gas phase reactions with a composite powder media.

The effect of powders homogenisation conditions on the synthesis of yttrium aluminium garnet (YAG) by a solid-state reaction

The work presents results of research on the influence of the state of homogenisation of reagent powders i.e. aluminium oxide and yttrium oxide on the synthesis of yttrium aluminium garnet. Fine powders of commercial aluminium oxide and yttrium oxide were mixed in the same manner in a laboratory ball mill but under four different conditions. Three batches of powders were prepared in water of various pH values, selected on the basis of the zeta potential measurements, and one batch was prepared in propanol. They were consolidated by filter pressing and then sintered in air at a temperature from 900°C to 1700°C for 1h, with heating rate of 5°C/min. Samples were subjected to dilatometric studies, phase composition determination, measurement of apparent density and pore size distribution, as well as a microscopic examination. Mixing environment affected, to a given extent, almost all the features of green, and partially sintered materials as well as course changes of linear dimensions. As a result, the relative densities of samples sintered at a maximum temperature ranged from 58.31% to 98.25%. The highest density was achieved for the material originating from the suspension having a pH of 9.5, in which heterocoagulation occurred.

Effect of the composition of starting yttrium aluminum hydroxide sols on the properties of yttrium aluminum garnet powders

A technique has been developed for the synthesis of yttrium aluminum garnet sols aggregationstable in water as a dispersion medium. Depending on the type of precursor used, the temperature of yttrium aluminum garnet formation varies from 900°C to 1100°C. We have obtained yttrium aluminum garnet nanopowders with an average particle size from 40 to 300 nm, depending on the aluminum yttrium hydroxide hydrosol synthesis procedure and annealing temperature.

Preparation of weakly agglomerated yttrium aluminum garnet powders by burning a mixture of yttrium aluminum hydroxynitrates, urea, and acetic acid

We have optimized the composition of a mixture of aluminum yttrium hydroxynitrates, urea, and acetic acid for the self-propagating high-temperature synthesis of yttrium aluminum garnet (YAG) powder. The powder prepared in this way offers a low degree of agglomeration, and the ceramic produced from it has a low carbon content. A technique has been proposed for carbon determination in YAG ceramics through gas chromatographic analysis of the gaseous products of carbide hydrolysis after the dissolution of the ceramic in pyrophosphoric acid.

Single step synthesis of yttrium aluminum garnet (Y 3Al 5O 12) nanopowders by mixed fuel solution combustion approach

A single step synthesis of single-phase Y 3Al 5O 12 (YAG) nanopowders via solution combustion using a fuel mixture (urea + glycine) approach, without high temperature calcinations, is being reported for the first time. Solution combustion was carried out in furnace pre-heated at 700 °C. The use of individual fuels did not lead to the formation of YAG directly from the combustion reaction. FTIR of combusted product showed peaks characteristic of YAG in case of mixed fuel. TGA revealed negligible weight loss indicating that reaction mixture containing the stoichiometric ratio of metal nitrates, urea and glycine triggered a vigorous combustion reaction forming single-phase nanocrystalline YAG. X-ray diffraction of combusted powder confirmed formation of phase pure YAG. Nanometric particles with size range from 40 nm to 60 nm were obtained with uniform morphology by TEM.

ChemInform Abstract: Synthesis of Yttrium Aluminum Garnet by the Glycothermal Method.

The reaction of a stoichiometric mixture of aluminum isopropoxide and yttrium acetate in 1,4-butanediol at 300°C yielded crystalline yttrium aluminum garnet having an approximate particle size of 30 nm. No other phases were detected. The use of ethylene glycol in place of 1,4-butanediol afforded an amorphous product.

English

The synthesis of yttrium aluminum garnet (YAG) (Y3 Al5O12) nanopowder was carried outby sol-gel method. Y(NO3)3.6H2O, Al(NO3)3.9H2O in the presence of citric acid as complexing agent were used as starting materials. YAG nanopowder was characterised by FTIR, TGA, andXRD. To get phase-pure nanocrystalline YAG powder at relatively lower temperature, calcinationat various temperatures was studied and calcination temperature was optimised. Particle size,estimated by XRD using Scherrer's equation, was found to be 28Œ35 nm which was further confirmed by transmission electron microscopy. The particle morphology was studied by SEM. Defence Science Journal, 2008, 58(4), pp.545 -549 , DOI:http://dx.doi.org/10.14429/dsj.58.1675

Synthesis of yttrium aluminum garnet (YAG) powder by homogeneous precipitation combined with supercritical carbon dioxide or ethanol fluid drying

YAG precursors were synthesized by the urea method in aqueous solution using supercritical carbon dioxide and ethanol fluid drying technique, respectively. The composition of the precursors, the phase formation process and the properties of the calcined powders were investigated by means of XRD, IR, TG/DSC, BET, TEM and SEM. Compared with the classically prepared powders at room temperature in air, the amorphous precursor dried by supercritical CO 2 fluid was loosely agglomerated and directly converted to pure YAG at about 900 °C. The resultant YAG powders showed good dispersity with an average crystallite size about 20 nm and specific surface area of 52 m 2 g −1. However, the precursor dried by supercritical ethanol fluid was crystalline. Extensive phase segregation occurred during the drying process and resulted in the formation of separate phases such as monoclinic Y(OH) 3 and pseudoboehmite. YAM and YAP phases appeared in the calcination process and phase pure were not detected until 1200 °C.

Electrochemical Synthesis of Thin Film YAG on Inconel Substrate

A novel method of electrochemical synthesis of yttrium aluminum garnet (YAG) thin-film coating on IN617 has been successfully developed in the mixture of Y(NO 3 ) 3 and Al(NO 3 ) 3 aqueous solution. The coating films were further annealed and characterized by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The coating film was composed of hydrated Y(OH) 3 and Al(OH) 3 , the physically adsorbed water evaporated between 25 and 103°C, dehydrated into Y(OH) 3 and Al(OH) 3 between 103 and 400°C, condensed into YOOH and AlOOH between 400 and 890°C, and finally transformed into single-phase YAG (Y 3 Al 5 O 12 ) between 890 and 1000°C. The YAG coating film with a thickness about 2 μm revealed the uniform and adherent interface on the substrate.

Computer simulation of synthesis of yttrium aluminum garnet

A mathematical model of synthesis of yttrium aluminum garnet is presented and used for computer simulation of the synthesis. The model is based on the reaction-diffusion equations. The model takes into concideration structure of the initial reaction’s components. The digital simulation was carried out using the finite difference technique. Relations between rates of reaction and diffusion was investigated.

Mechanochemical solid reaction of yttrium oxide with alumina leading to the synthesis of yttrium aluminum garnet

Dry grinding of Y2O3 and transition aluminas was conducted, using a planetary ball mill under atmospheric conditions, to synthesize yttrium aluminum garnet (Y3Al5O12, YAG). The Y2O3 reacts mechanochemically with the transition aluminas to form YAlO3 and YAG after 120 min of grinding. No reaction occurs when the Y2O3 was ground with hard corundum or soft gibbsite. Grinding the Y2O3 for 360 min with an alumina prepared by heating at 400 °C leads to a nearly amorphous phase of YAG. A well-crystallized phase of YAG was obtained easily by calcining the ground sample at 700 °C. The calcined YAG fine powders contain agglomerates that consist of nanosized primary grains.

Comparison of citrate–nitrate gel combustion and precursor plasma spray processes for the synthesis of yttrium aluminum garnet

The influence of synthesis conditions on the formation of yttrium aluminum garnet (YAG) powders starting from the same solution precursors was investigated by employing a citrate–nitrate gel combustion process and a precursor plasma spraying technique. YAG powders were formed at ≥500 °C, through the citrate–nitrate gel combustion process, without any intermediate phase formation. Time-resolved x-ray experiments were performed for the first time on these citrate–nitrate precursor materials to understand their mode of decomposition. The in situ data confirmed a single-step conversion to YAG from the precursor powder without any intermediate phase formation. Ex situ experiments also produced similar results. However, the use of the same citrate–nitrate precursor solution as a liquid feedstock material in the precursor plasma spraying technique revealed an entirely different transformation mechanism to YAG through intermediate phases like H–YalO3 and O–YalO3.

Translucent yttrium aluminum garnet: Microwave-assisted route to synthesis and processing

A novel and fast microwave route is described for the synthesis of yttrium aluminum garnet (YAG) and for its sintering to translucent bodies. Precursor was made by microwave decomposition (20 min) of aluminum tri-sec-butoxide and yttrium nitrate dissolved in ethyl acetate. The precursor, conventionally calcined at 1000 °C (1 h), was sintered in microwave using SiC as secondary heater for just 35 min. Resulting translucent YAG has a microhardness (HV) of 18.1 GPa and fracture toughness (KIC) of 4.3 MPa m1/2. A 0.86-mm-thick sintered pellet exhibits approximately 45% transmission for 520-nm radiation. The entire microwave process requires less than 3 h.

Synthesis of Yttrium Aluminum Garnet from a Mixed‐Metal Citrate Precursor

Yttrium aluminum garnet (YAG, Y3Al5O12) was synthesized using a polymeric precursor derived from a mixed‐metal citric acid/ethylene glycol/ethanol solution. YAG was found to crystallize directly from an amorphous precursor beginning at temperatures as low as 600°C within 1 h in air. The polymer resin concentration was found to have an effect on the temperature of crystallization initiation. However, all precursors produced a well‐crystallized YAG powder within 1 h at 800°C in air. Formation of phase‐pure YAG in an argon atmosphere did not occur until heating for 1 h at 1000°C. An optimum cation‐to‐resin ratio to maximize reactivity provides a polymeric network to ensure a homogeneous dispersion of cations, yet minimizes cation diffusion distances within the char by limiting excess free carbon after polymer pyrolysis.

Synthesis of oxide powders by way of a polymeric steric entrapment precursor route

A polymerized organic–inorganic complexion route is introduced for the synthesis of yttrium aluminum garnet, YAG (Y3Al5O12) and cordierite (Mg2Al4Si5O18) powders. Long-chain polymers such as polyvinyl alcohol (–[CH2–CHOH]-n or PVA) or polyethylene glycol (H[O–CH2–CH2]nOH or PEG) were used as the organic carriers for a precursor ceramic gel. Calcined powders were very porous and homogeneous in distribution of components. Experimental studies by differential thermal analysis and thermogravimetric analysis, x-ray diffraction, solid-state nuclear magnetic resonance, and Fourier transform infrared spectrometry indicated that metal-ion chelation is not the primary mechanism for obtaining molecularly homogeneous precursor powders. Water-soluble cations of mixed oxides in the PVA or PEG process were sterically entrapped in the entangled network and resulted in fine and pure, mixed oxide powders.